As a short-range wireless communications technology, a Wireless Fidelity (Wi-Fi) technology is widely used due to characteristics such as a free spectrum and a high transmission rate. For example, Wi-Fi wireless access devices are disposed on occasions such as a household, an enterprise office, and a large conference room. A user can access a network anytime anywhere by using a terminal such as a mobile phone or a tablet computer that has a Wi-Fi network interface.
In a scenario such as an enterprise office or a large conference room, multiple wireless access devices are usually deployed to implement contiguous coverage, and a terminal is allowed to perform roaming switching between different wireless access devices. In a specific application, when a user who carries a terminal having a Wi-Fi network interface moves, the terminal detects signal strength of a currently connected wireless access device. When the terminal detects that the signal strength of the currently connected wireless access device becomes weak and is less than a switching threshold of the terminal, the terminal starts a roaming process and scans signal strength of a surrounding wireless access device. The switching threshold of the terminal is a critical value of the signal strength of the wireless access device from which the terminal starts roaming. When detecting another wireless access device having relatively strong signal strength, that is, a target wireless access device, the terminal directly establishes an association with the target wireless access device or establishes an association with the target wireless access device using the currently connected wireless access device. In addition, to improve network performance, when detecting that signal strength of the terminal is less than a switching threshold of a wireless access device in an enterprise network, the wireless access device starts a process of putting the terminal offline to release an association with the terminal. The switching threshold of the wireless access device is a critical value of the signal strength of the terminal with which the wireless access device actively releases the association.
Generally, both the switching threshold of the terminal and the switching threshold of the wireless access device are preset. Specifically, because a transmit power of the wireless access device is greater than a transmit power of the terminal, in a same transmission condition, the signal strength of the wireless access device detected by the terminal is relatively strong while the signal strength of the terminal detected by the wireless access device is relatively weak. Therefore, a scenario may occur in which the signal strength of the terminal detected by the wireless access device has reached the switching threshold of the wireless access device while the signal strength that is of the wireless access device and that is detected by the terminal is still greater than the switching threshold of the terminal. That is, the terminal has not started roaming but the wireless access device has put the terminal offline, and consequently the terminal is disconnected from the network.
To prevent the terminal from being put offline by the wireless access device before the terminal starts roaming, in an actual application, the switching threshold of the terminal is greater than the switching threshold of the wireless access device, so that the terminal has started roaming before being put offline by the wireless access device. However, if the switching threshold of the wireless access device is set to be excessively low, a new problem occurs. The terminal detects that the signal strength of the wireless access device is greater than the switching threshold of the terminal, while the wireless access device detects that the signal strength of the terminal is relatively weak but is still greater than the switching threshold of the wireless access device. In this case, the terminal cannot start roaming, and the wireless access device cannot actively release the association with the terminal, either. Consequently, the terminal is still associated with the wireless access device whose signal strength is relatively weak, and user experience of network access is affected.
Based on the foregoing reason, an urgent problem currently to be resolved is how to set a switching threshold of a terminal and a switching threshold of a wireless access device that match each other, so that the terminal has started roaming to find a target wireless access device when the wireless access device is to release a wireless communication connection to the terminal.